Error 1010 O

Safety first

1. If you smell gas, leave the property immediately and call the gas emergency number. Do not attempt any checks or repairs.

2. Do not work on live electrical parts or open the boiler casing unless you are qualified. Isolate the boiler electrical supply at the fused spur or isolator before any internal inspection. If you are not trained, do not remove panels or touch internal components.

3. Repeatedly resetting a locked boiler will not fix an underlying fault and can delay a proper repair. If resets don’t clear the code, stop and get professional help.

Initial homeowner checks (safe, simple checks)

1. Reset the boiler once using the reset procedure in your manual (press and hold the reset button or follow the dial method for 3 seconds). Wait a minute to see if the code clears and the boiler restarts.

2. Check any external controls that connect to the boiler (room thermostat, smart controller, programmer). Ensure they are powered on, their batteries (if used) are good, and they are calling for heat. Switch them off and on and check that their display/LEDs show normal operation.

3. Look for any visible low-voltage cable runs between the boiler and external controls that you can access without opening the boiler. Inspect for obvious cuts, crushing, rodent damage, or water ingress at visible junctions and terminal boxes.

4. Note and photograph the exact error code and any other displayed codes, and record when the fault happened and what controls were active. This information helps the engineer diagnose faster.

Further checks (only if you are confident, can safely isolate power, and the boiler manual allows access)

1. Isolate the boiler electrical supply at the isolator and confirm power is off. If you are unsure how to do this, stop and call an engineer.

2. With power off, check any external plug-in modules or junction boxes that connect to the EMS bus and make sure their connectors are pushed fully home and not corroded. Some room controllers and extension modules have removable plugs that can work loose.

3. If an external control has a user-accessible fuse (for example in a plug or remote module), replace that fuse only if you can access it without opening the boiler. Do not attempt to replace internal fuses or PCB-mounted fuses yourself.

4. If you have a multimeter and know how to use it safely, you can check for continuity along exposed sections of bus cable and inspect connectors for correct wiring continuity. Do not probe live circuits and stop if you are uncertain.

When to call a professional

1. Call a Gas Safe registered heating engineer if: the reset does not clear the error, you find damaged or corroded cables, connectors inside the boiler appear loose, any internal fuses may be blown, or you are not comfortable doing the isolation and inspection yourself.

2. Ask the engineer to check EMS-bus continuity, connector seating at the control PCB, any in-line fuses related to the bus, and associated external controls. They will have the correct spare cable, connectors, and replacement fuses, and can test the control board and modules safely.

3. Provide the engineer with the boiler model, serial number, the 1010 O error code, what checks you have already done, and any photos you took. This speeds diagnosis.

Final notes

1. Do not attempt internal repairs, replace PCB components, or alter gas valves yourself. These actions are hazardous and invalidate warranties and safety certificates.

2. This guidance does not include repair cost estimates. A qualified Gas Safe engineer will diagnose the cause and advise the appropriate repair, replacement of an EMS cable or connectors, or any further work required.